Guarantees and Product Warranty (Details 2) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Movement in Standard Product Warranty Accrual
Warranty liability, beginning balance	$ 1,354	$ 1,426
Reduction in liability (payments)	(220)	(874)
Increase in liability (new warranties)	219	802
Warranty liability, ending balance	$ 1,353	$ 1,354